ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 73 



The cell-juice prepared by the authors undergoes a very considerable 

 auto-fermentation, in some instances exceeding that given by a mixture 

 of the same juice and cane-sugar. A dilution of 1-2 with water or 

 physiological salt solution practically stops all fermentative activity. 

 Only with a very active cell-juice does the ratio between the alcohol 

 and carbon dioxide formed approximate to that found in ordiuary alco- 

 holic fermentation. When the cell-juice is allowed to act on sugar — 

 •either cane-sugar or dextrose — the quantity of sugar which disappears 

 is considerably in excess of that which can be accounted for by the 

 production of carbon dioxide and alcohol. These results appear to lead 

 in the direction not of an enzyme explanation of the process, but rather 

 of a theory which refers the phenomenon to the vital activity of the 

 yeast-cell protoplasm. 



In connection with the foregoing, Prof. J. R. Green * ventures to 

 disagree with the conclusion that the yeast-juice exhibits the vital 

 activity of the yeast-cell protoplasm ; for he has found that an active 

 preparation could be obtained by grinding the yeast with kieselguhr in 

 such proportion that a perfectly dry impalpable powder resulted, and 

 then extracting the latter with a solution of cane-sugar. It is hardly 

 credible that protoplasm without the protection of cell-walls can resist 

 desiccation. The action of the extract was considerable in the presence 

 of antiseptics which, in the proportions used, were inevitably and rapidly 

 fatal to the life of protoplasm. 



Rabenhorst's Cryptogamic Flora of Germany, &c. (Fungi Imper- 

 fecti).f — Volume I. of this important work by A. Allescher is now 

 complete with the publication of two more parts, 73 and 74. The large 

 genus Bhabdospora comprises altogether 142 species. It is followed by 

 the comparatively small genera Collonema (4 sp.), Tricltoseptoria (1 sp.), 

 Phleospora (10 sp.), Phlyctaena (15 sp.), Sphserograplrium (4 sp.), Corna- 

 laria (4 sp.), Eriospora (1 sp.), Dilophospora (1 sp.), Septoriella (1 sp.), 

 Cytosporina (24 sp.), Micula (2 sp.), and Micropera (11 sp.). The next 

 section, the Hyalophragmia?, is characterised by its elongated or fusiform 

 spores with two or more septa, hyaline or nearly so, and is made up of 

 three genera, Stagonospora with 78, Blastomyces with 2, and Kellermania 

 with 1 species. 



Dictyophora Ravenelii4 — C. S. Scofield gives an account of the 

 structure and development of this fungus belonging to the Pkalloideae, 

 and a somewhat aberrant member of the genus. The points which he 

 regards as of special interest are these. The mycele of the plant is of 

 considerable structural importance. There are borne upon it certain 

 organs which seem to function as storage places for reserve material. 

 There is, in the young mycelial threads, very good evidence of the 

 occurrence of cell-fusion previous to, or in intimate connection with, 

 the formation of the sporophore. The indusium cannot be considered 

 as homologous with the indusium of normal members of the genus 

 Dictyophora, but is rather the persistent remnant of tissue which is 

 completely broken down in most other plants of the order. 



* Nature, lxiii. (1900) p. 106. 



t Leipzig. 1901, 1016 and viii. pp. and numerous figs. Cf. this Journal, 1900, 

 p. 620. X Minnesota Hot. Studies, 2nd ser., 1900, pp. 523-36 (3 pis.). 



